This backport changes made by EE to the files in the scripts/ directory.
This comes with a few changes to some scripts to make them work in the
single codebase setup.

Changes all calls to data_source_exists? to table_exists?
since that is the intent of these calls

None of this code can be reached any more, so it can all be removed

Rather than have it checked only as part of gitlab:db:configure, we will
instead have it as a pre-req for every db:migrate command

Set the mininum supported migration version to be the schema version as
of 11.11.0, and errors you if that is not detected during
gitlab:db:configure

This adds a conditional statement before truncating the
`schema_migrations` table.

This comit also ports this code to Rails 5.

If doing a schema load, the post_migrations should also be marked as up,
even if SKIP_POST_DEPLOYMENT_MIGRATIONS was set, otherwise future
migration runs will be broken.

If you called rake gitlab:db:drop_tables before running gitlab-ctl
reconfigure (or rake gitlab:db:configure)

These new checks can be used to check if migrations require downtime or
not (as tagged by their authors). In CI this compares the current branch
with master so migrations added by merge requests are automatically
verified.

To check the migrations added since a Git reference simply run:

    bundle exec rake gitlab:db:downtime_check[GIT_REF]

!4318 broke the gitlab:db:drop_tables functionality for PostgreSQL.

Closes #15259

Colorize is a gem licensed under the GPLv2, so we can’t use it in GitLab without relicensing GitLab under the terms of the GPL. Rainbow is licensed under the MIT license and does the exact same thing as Colorize, so Rainbow was added in place of Colorize.

The syntax is slightly different for Rainbow vs. Colorize, and was updated in accordance.

The gem is still a dependency of Spinach, so it’s included in the development/test environments, but won’t be packaged with the actual product, and therefore doesn’t require we relicense the product.

An attempt at relicensing Colorize was made, but didn’t succeed as the library owner never responded.

Rainbow library: https://github.com/sickill/rainbow
Relevant issue regarding licensing in GitLab's gems: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3775

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

closes #15259

Switch the gitlab:db:configure task to use tables.any? instead of looking specifically for the schema_migrations table